radiopharmaceutical

Syllable breakdown

Dictionary meaning

a radioactive chemical compound used in nuclear medicine for diagnostic imaging or therapeutic purposes, consisting of a targeting molecule (the pharmaceutical) attached to a radioactive isotope (the radionuclide); diagnostic radiopharmaceuticals emit gamma rays or positrons that are detected by imaging equipment such as gamma cameras (for SPECT) or PET scanners, enabling the clinician to visualise the biodistribution and metabolic activity of the compound in the patient's body; therapeutic radiopharmaceuticals deliver localised radiation doses to target tissues — most commonly cancer cells — using the pharmaceutical's biological targeting to achieve selective irradiation; common diagnostic radiopharmaceuticals include technetium-99m-labelled compounds (bone scans, ventilation-perfusion scans), FDG (fluorodeoxyglucose) labelled with fluorine-18 for PET, and iodine-123 or iodine-131 for thyroid imaging and therapy; the field of targeted radionuclide therapy — using radiopharmaceuticals to treat cancer — is one of the most rapidly expanding areas of oncology

Examples

• The radiopharmaceutical technetium-99m methylene diphosphonate was used in the bone scan to detect skeletal metastases.
• Lutetium-177 PSMA, a therapeutic radiopharmaceutical targeting prostate-specific membrane antigen, has shown significant benefit in metastatic castration-resistant prostate cancer.

Synonyms: radiotracer, radiolabelled drug, nuclear medicine agent